170 Proceedings of Indiana Academy of Science. 
SULPHUR DIOXIDE AS A SOURCE OF VOLCANIC SULPHUR. 
JACOB PAPISH, Purdue University. 
The reaction expressed by the equation H2S + SO: = H:0 + 2S was 
investigated by Cluzel’ as far back as 1812. This reaction was accepted 
by geologists and chemists* as being back of the origin of volcanic sul- 
phur: hydrogen sulphide and sulphur dioxide gases, escaping from vents 
and fumaroles, come in contact and bring about the formation of sul- 
phur. Brun* opposes this theory of the origin of sulfatara sulphur, and 
he, in turn, is opposed by others. The reader is referred to the literature 
on geochemistry for details.’ 
In case of sulphur deposition, where hydrogen sulphide is detected 
as a voleanic exhalation, it is supposed that the sulphur is formed as a 
result of the partial oxidation of the hydrogen sulphide.° 
While investigating the flame reactions of the sulphur group of 
elements, I noticed that when a mixture of sulphur dioxide and illu- 
minating gas is heated in a glass tube, an opalescence is produced 
due to the precipitation of sulphur. ITlluminating gas is a mixture 
of different reducing gases, and, on the whole, the reaction resembles 
the one described by Berthelot,’ which is expressed by the equation 
SO: + 2CO = 2CO:+S. Since voleanic exhalations contain carbon 
monoxide, as well as methane and hydrogen, then why not suppose that 
voleanic sulphur is formed from sulphur dioxide through a reaction of 
reduction, say, with carbon monoxide? The sulphur thus formed will 
have to cool and condense before it comes in contact with oxygen, other- 
wise it will burn back to sulphur dioxide. Some means of sudden cool- 
ing is especially favorable for its formation instantly upon reduction 
from sulphur dioxide. Such a means is to be found in the case of the 
sulphur recovered from Lake Ponto, which is a crater lake in the south- 
western part of Kunashiri Island, Japan.’ The water of this lake is 
strongly acid® and has a temperature of 40° C. Around the margins 
1 Ann. Chim. Phys. 84, 162 (1812); Jour. Phys. Chem. 15, 1 (1911). 
* Ries’ ‘“‘Economie Geology’’, 4th ed., p. 293; Roseoe and Schorlemmer’s ‘Treatise 
on Chemistry” 1, 365 (1905); Erdmann’s ‘‘Lehrb. anorg. Chemie’’, 2nd ed., p. 235 (1900). 
3 Chem. Zeit. 15, 127 (1909). 
'Clarke’s “Data on Geochemistry”, 3rd ed., pp. 270 and 575. 
* Habermann: Zeit. f. anorg. Chem. 38, 101 (1904). 
® Compt. rend. 96, 298 (1883). 
*Y. Oinouye: Jour. of Geology 24, 806 (1916). 
° Professor Oinouye, in a private communication dated April 29, 1918, informs me 
that the water smells of sulphur dioxide 
